Puzzle 81: Fell from the Sky

Skyscrapers Latin square: Put a number between 1 and 7 into each cell inclusive such that each row and column contains exactly one instance of each number. If we consider the numbers as heights of buildings, each number outside the grid tells the number of buildings visible from that point, looking into the grid. For example, an observer to the left of the sequence 1426375 sees four buildings (1,4,6,7; other buildings are hidden by taller buildings to the left).

Expected difficulty Medium • Answer • Comment/E-mail if you want a solution to be published

Puzzle 81: Fell from the Sky
Skyscrapers

This is the first in the series of the rejected puzzles for FAST, a joke test for April Fools Day. As described in a post in the discussion thread, my initial idea was “normal-sized” puzzles (even though I actually had 12×12’s and not 10×10’s), but with answer keys that are trivial to obtain. This, in some cases, lend to actually trivial puzzles too, but I don’t really like that, and hence here’s a handpicked collection of puzzles that I deem to be interesting enough even with the trivial answer key restriction. (Thus the title follows; the puzzles are those that “fell from the sky”, failed to be picked for the party.)

Deception Preview 9: Lines of Circles

Skyscrapers Kropki Put a number between 1-6 inclusive in the grid (the black-bordered square) so that each number appears exactly once in every row/column. Afterwards, interpreting the numbers as heights of buildings, put a number in each cell outside the grid (observer) that tells the number of visible buildings from that position looking into the grid. Taller buildings block shorter ones. For example, if a row has 25341 in that order, an observer from the left will see two buildings (2,5) and from the right will see three buildings (1,4,5).

In addition, if there is a black circle between two cells, one of the numbers in those cells must be exactly twice the other. If there is a white circle between two cells, the two numbers in those cells must differ by one. (There can be either circle between 1 and 2.) The absence of circles doesn’t imply anything.

Answer key: Enter the unit digits (last digits) of the numbers in the cells in the row/column. Only enter the buildings, not the observers.

Difficulty 4.0/10 • Target times 02:00 04:00 07:00 20:00
Solution Answer key (highlight →) 563124,362154 • PNG (not uploaded) • ZIP of PDF (not uploaded) • DOCX (not uploaded)

Deception Preview 9: Lines of Circles
Skyscrapers Kropki

Ninth preview puzzle. That ends the Deception preview series. Reminding you that the link is here, and it will start in approximately 31 hours. Good luck!

…yes. This puzzle is posted out of schedule. There’s a long story, but basically Prasanna Seshadri is also going to testsolve this. Or solve this, since it’s official. I don’t know. Whatever. But he wanted the last preview puzzle, and I’m on bed already (yes, this paragraph is hot from the stove), and I don’t have the copy on my phone. So, yeah. Sorry if you find the broken schedule annoying. But earlier never hurts, does it?

About this puzzle itself, it’s supposed to make the shape of P. Or not, I don’t know. I totally forget whether this is intentional or accidental. I toyed with the possibility of lined circles, and this is what happens.

FFF 8: Fillocity is Back

Fancy Fillomino February: This is a series of 28 (twenty-eight) 7×7 Fillomino puzzles over the February. Every 00.00 UTC+7 a new puzzle will be up. The basic Fillomino rules apply unless otherwise indicated.

Skyscrapers Fillomino In addition to the regular Fillomino rules, the numbers must also satisfy the Skyscrapers clues. If the numbers are interpreted as buildings of said height, a number indicates the number of buildings visible from that position looking into the grid in the corresponding row/column. A building is visible if it’s not behind another building with equal or greater height.

Difficulty 2.0/10 Master target 0:20 Expert target 1:30

FFF 8: Fillocity Is Back
Skyscrapers Fillomino

Well, the mayor of Fillocity somewhere outside Manne asked Sky. Again. This time it’s not something insane though.

Puzzle 54: Missing Buildings Information

Skyscrapers Kropki. Inside the bordered square, put the numbers 1-6 to the cells such that each row and column contains exactly one of each number. Outside the bordered square, put the number of visible “buildings” from that direction looking inside the grid (numbers act as buildings and taller buildings hide shorter buildings, so 24135 sees 3 buildings (2,4,5) from the left and 1 building (5) from the right). There are Kropki circles appearing. For each black circle, one of the numbers on its sides must be exactly twice of the other. For each white circle, the two numbers must be consecutive. There is no restriction for cells not separated by circles, unlike regular Kropki.

Consider yourself done if you get the numbers inside the grid.

As perceived by the author…
Difficulty: 4.5/10
Target time: 2:30

This city is a bit insane. Not only some buildings are simply “an adjacent building stacked twice” or “an adjacent building with one ‘ground’ floor”, but there aren’t actually any people managing the heights; only some observers seeing from the outside of the grid. And it even e-mailed Sky the backed up information about a district in the city after the city had lost the record somewhere, asking Sky to solve it. Apparently the city cannot afford sending people to inspect the heights…but then, good news to Sky, as he’s even more well-known as a puzzle solver.

Puzzle 54: Missing Building Information
Skyscrapers Kropki

A preview of my upcoming LMI test, Deception in May 2013. Or in June 2013, depending on my business. Skyscrapers Kropki is one of the nine genres that are in the test.

Puzzle 55 in 24 more hours!

Also, seems like there are stupid bugs on images. If you see any image to be heavily distorted, just click to view.

Puzzle 24: Skyscrapers

Skyscrapers. Medium, unless I overestimate the difficulty of a Skyscrapers.

Puzzle 24: Skyscrapers

What is this? A small-grid puzzles batch? You’ll find out the answer at Puzzle 25, within, say, 10 hours.

Puzzle 19: Skyscrapers

Skyscrapers. Put a number between 1 and the length of a side of the grid such that each number appears exactly once in each row and column. If the numbers represent heights of buildings, the numbers outside the grid tell the number of visible buildings from that point looking into the grid, with higher buildings block lower ones in visibility. This one is somewhat easy.

Puzzle 19: Skyscrapers

Easy enough isn’t it? Puzzle 20, the 17×17 puzzle, will be a Fillomino and will be posted in 12 hours from this post.

Special Puzzles 2-4: Not Your Usual Logic Puzzles

Not your usual logic puzzles. For proof, see Special Puzzle 1 (no pun intended).

To be taken as very short (read: 10 seconds or so) (hopefully-)fun diversions when solving ridiculously tough puzzles. They are all ridiculously easy for that reason…maybe.

Also, I have prepared all the way to Puzzle 21. They will appear at 12 hours from another, so Puzzle 18 will be 12 hours from now and Puzzle 21 will be 48 hours from now. Puzzle 18 is a KenKen.